The invention relates generally to calling card dialing for cellular telephones and more specifically to a method and apparatus for automatic execution of same.
Calling cards are issued, for example, to subscribers of long distance service so that they may access a long distance carrier from any local network. The primary advantage to having a calling card account is the ability to make long distance calls at favorable rates through any local exchange. Consolidation of billing is yet another advantage. Known procedures for making calls with a calling card account require that the subscriber dial a predetermined number to access the independent carrier network. A successful connection to the carder network is usually signified by the transmission of a tone or prompt. Upon receipt of this tone or prompt, the user or subscriber then dials the telephone number of the call to be placed. The carrier network then responds with another prompt to the subscriber to enter a verification code depending on the card used. If the user responds with a valid number, the desired connection is then completed through the independent carrier network.
By the way, for purposes of this discussion, the terms user and subscriber are used interchangeably. It is understood that the user need not be a subscriber to a particular carrier network, he/she can be the person who is using the telephone at a given time.
A disadvantage to the usage of a calling card account is that the procedure required to complete a call requires many keystrokes. The user must also be able to recall both the access number and the user identification number to successfully make use of the service. With regard to the use of calling card accounts on cellular mobile telephones, it is a matter of safety and convenience to reduce as much as possible the number of keystrokes required for making a call. A problem can arise, particularly in cellular telephones used in automobiles, where it is dangerous to divert the driver's attention from the road to the telephone. As an additional benefit, any simplification to the procedure for placing calls through a calling card account would likely result in increased usage thereof and a maximum of cost savings.
It is desirable to provide a simple, automatic procedure that would allow a user to place calling card calls. That each carrier may have a different procedure for executing calling card calls presents a challenge to the automation of the procedure. This is further complicated by the need to make any sequence of operations easy to program by a novice user. Some cellular telephones have one (or more) special memory locations intended to be used for calling card codes (the contents of such can be changed or viewed by first entering a personal code). The OKI 1150 Handheld Telephone User's Guide and Warranty, OKI Telecom, Suwanee, Ga., pp. 24, 26, 31, describes a calling card mode which can be entered from a menu. Once in the calling card mode, all successive numbers are automatically charged to a preprogrammed sequence, until the calling card mode is turned off. This operation is disadvantageous because the mode must be turned on to make long distance calls and turned off before attempting to make non-calling card calls. If the mode is not disabled, an error may result and some calls will be erroneously billed to the credit card.
It is desirable to provide an automatic calling card sequence which does not require a special mode. It is also desirable to provide an initial sequence which alerts the telephone to the automatic calling card sequence. It is further desirable to provide an automatic calling card sequence which is easy to invoke and is only valid for each time the sequence is initiated.